Delve into building Android apps using Kotlin. Gain hands-on experience with tools like Groovy and XML while creating a Travel Blog app for your portfolio.

This course is for anyone looking to build their own Android applications. Ever since Google announced that Kotlin is the language of choice for Android development, Kotlin has become increasingly popular.

In this course, you’ll take a hands-on, project-based approach to developing Android applications. You’ll work with the most common tools that Android developers use every day, including Kotlin, Groovy, and XML. As you learn, you’ll build a fully functional Travel Blog Application that will be a great addition to your portfolio.

By the end of this course, you’ll have tangible experience building an Android application and be ready to build even more complex projects.

John

Great practical approach to learn Android Development

Engineer

Modern Android App Development with Kotlin

This lesson explains the different options available on Android to cache the data for offline support.

# Preferences

One of the most common ways to persist data on the Android phone is to use [SharedPreferences](https://developer.android.com/training/data-storage/shared-preferences).

The shared preference is basically a key-value store solution for a small amount of data with a built-in memory cache. We have already used shared preferences to persist in the login state.

# Files

When the data is too big for the shared preference, we can always use plain old files.

```kotlin
val filename = "myfile.txt"
val fileContents = "Hello world!"
openFileOutput(filename, Context.MODE_PRIVATE)
        .write(fileContents.toByteArray())
```

The problem with files is that we need to convert our data to a format that can be stored and reconstructed later, such as a JSON string, which is not efficient in some cases.

# SQLite

Fortunately, in *Android*, we can create a local database called *SQLite*. 

The `android.database.sqlite` package contains all sorts of API to work with databases - from simple queries to complicated joins. While the *Android* *SQLite* package contains everything we need, the API is pretty basic and requires us to write a lot of boilerplate code. For these reasons, Google decided to write an abstraction on top of the `android.database.sqlite` package to make it easier to work with a database.

This layer is available as a separate library called *Room*.  In the next lesson, we are going to learn how to use the Room database to store and access blog articles.

Discover how to improve user experience by implementing offline support in this chapter.


Android Ecosystem

Hello World

Travel Blog - Login Screen

Travel Blog - Details Screen

Travel Blog - List Screen

Travel Blog - Search & Sort

Travel Blog - Offline

Conclusion

Caching Solutions